Development and psychometric evaluation of the Japanese version of the Physical Effort Scale

Background Physical inactivity is a global public health concern, and bridging the gap between intention and behavior is critical to promoting physical activity (PA). The Physical Effort Scale (PES) assesses individual tendencies to approach or avoid physical effort, which may help explain this gap. To facilitate cross-cultural research on PA behavior, this study developed and validated a Japanese version of the PES (PES-JP). Methods We translated the PES into Japanese according to established cross-cultural adaptation guidelines. An online survey was conducted among 400 Japanese adults aged 20 to 59 years. Exploratory and confirmatory factor analyses were conducted to examine structural validity. Construct validity was assessed by examining concurrent, convergent, and discriminant validity, following the analytic approach of the original PES study. Concurrent validity was assessed using self-reported PA levels from the International Physical Activity Questionnaire. Results Structural validity was supported by a two-factor structure (approach and avoidance), consistent with the original scale. Internal consistency was high for both subscales (α = .92 for approach, .87 for avoidance). Concurrent validity was demonstrated by associations between PES-JP scores and PA levels: the approach score was positively associated with moderate-to-vigorous PA (MVPA; standardized coefficient: β = .18) and negatively with sitting time (β = − .19), while the avoidance score was unrelated to MVPA but positively associated with sitting time (β = .20). The global score (approach – avoidance), which reflects the overall tendency to approach rather than avoid physical effort, showed a similar pattern to the approach score, being positively associated with MVPA (β = .12) and negatively with sitting time (β = − .23). Convergent validity was demonstrated through associations between all PES-JP scores (approach, avoidance, and global) and autonomous motivation, affective attitudes, and intentions (ps < .001). Discriminant validity was demonstrated through weak associations between all PES-JP scores and controlled motivation and instrumental attitudes (ps ≤ .028). Test-retest reliability was acceptable (ICC = .74 for approach, .64 for avoidance, .81 for global score). Conclusions The PES-JP is a psychometrically sound instrument for assessing tendencies toward physical effort in Japanese adults. The approach and global scores were associated with higher MVPA and lower sitting time, whereas the avoidance score was unrelated to MVPA but positively associated with sitting time. The PES-JP can support research on individual differences in PA behavior and contribute to cross-cultural investigations of how tendencies toward physical effort influence PA across diverse populations.